DX Dude

Field Day with a club is just a completely different experience, like you said you miss the social part and yeah thats kind of the whole point for a lot of people. the technical side gets spread around so nobody burns out, plus you usually end up learning a ton just from watching how the experienced ops run the pileups. i've done it both ways and solo is rewarding in its own way but if you have a decent club nearby it's worth showing up at least once to see what it's like.
as for Sweepstakes, dont let the complexity scare you off. yeah the multiplier system is a bit weird with sections instead of countries but once you get your head around it after the first hour or so it clicks. the 24 hour single op limit also means its not as brutal as something like CQ WW where people are going 48 hours and turning into zombies. i'd say go for it, worst case you learn a ton and get a feel for high rate domestic contesting which is its own skill set.

The theoretical improvement from 16 to 32 quarter-wave radials is about 1 dB, maybe less in real soil conditions. I went from 16 to 24 on my 40m vertical and honestly couldn't measure a significant difference on-air. Save your wire and focus on height instead.

yeah it's almost entirely a skill thing honestly, the first few passes are basically just chaos and then it starts to click. the inversed passband trips everyone up at first — if you tune your uplink up, your downlink moves down, so you have to get that muscle memory going before it becomes natural.
the hand-tracking yagi thing is rough but totally doable for low passes, people have worked satellites with a handheld and a rubber duck so dont let that discourage you. the bigger issue for me when i was starting out was not pre-setting my downlink before the pass even started. like you want to find your own signal before the satellite crests the horizon, even if its just on a beacon or noise floor, so you're not scrambling at AOS.
for the doppler — gpredict with hamlib should be handling it but you have to make sure the rig control is actually connected and responding. i had a whole situation where i thought it was working but the com port wasn't configured right and my radio was just sitting there static while gpredict thought it was tuning. check your rig control window in gpredict and see if the frequency display there is actually changing during a pass, that'll tell you if the link is live.
AO-73 is a good choice, passband isn't huge but activity is decent. give it like 5 or 6 passes before you judge whether it's working, the learning curve is steep but short

so i passed my technician exam on the 14th and been lurking on the local 146.520 simplex frequency just listening for a few days before i worked up the nerve to actually key up. finally did it yesterday, just said my callsign and that i was a new ham looking for a contact. guy came back almost immediately, we talked for maybe 10 minutes about nothing in particular, his antenna setup i think, and honestly i was so nervous i dont even remember half of what he said but it was great. hands were literally shaking a little when i was transmitting which is ridiculous because its just talking on a radio but whatever. anyway just wanted to share because i feel like ive been reading this forum for months leading up to my test and it feels good to finally have something to post about

honestly the biggest thing for me was just accepting that timing is everything and theres no shame in not getting through on the first day. i chased VP6R for like four days before i finally worked them and by the end i had their split patterns basically memorized. sometimes the best move is just waiting until the pile dies down a bit — like trying at 0200 local when half the competing stations have gone to bed.
also if you have any antenna at all that can be aimed, even a modest beam, point it and leave it. i see guys on the cluster complaining they can hear the DX fine but can't break through and then mention they're on a dipole. the math just isn't there sometimes and no amount of technique fixes a 6dB disadvantage in a pile of 500 stations

yeah what he said basically. i'll just add that i was in the same boat when i started and i kind of wish someone had told me to just pick LoTW first and not try to figure everything out at once. i spent like three evenings confused about certificate files and TQSL before i got it working lol. eQSL i set up in like ten minutes by comparison.
also some DX stations will only confirm one way so having both does actually come in handy eventually. but for 2m contacts honestly most people just use LoTW or sometimes nothing at all, the card culture is more of a thing with HF and DX chasing

so ive been running an old FT-450D for about 4 years now and honestly it served me well but ive had this itch to upgrade for a while. picked up a used IC-7300 last week from a guy in the club and i gotta say the waterfall display alone is worth it for me just to see whats happening on the band before i even key up.
but now im reading stuff about how the FT-891 is actually a better rig in some ways and the 7300 is basically just popular because of hype and the pretty screen and now im kinda spiraling a bit. anyone actually done a side by side? or even just used both at different points? my main thing is casual HF, some SSB ragchewing, might try some FT8 eventually. not a contester or anything serious like that.
also the previous owner had some weird audio settings tweaked and i cant figure out how to get the mic gain back to sounding normal. feels like im transmitting through a tin can right now

depends what band your thinking about too. 144 is probably the most active but needs the biggest antennas. 432 might be easier to get started on since the antennas are smaller but you need more power. i know a few guys doing 1296 eme with just one big dish and having decent luck
honestly though if your budget is tight maybe consider starting with aircraft scatter or meteor scatter first. similar propagation concepts but way less demanding on the wallet