Investigating TPS issues..

I'll try and keep this short and sweet. I'm a new minecraft admin with traditional IT experience. I have a small community server (12 actively playing typically) on 1.20.1 forge with 80 mods, hand picked. It's on shockbyte's best server, 16GB ram and realtime CPU, whatever that means. We moved from a different host where the server was crashing every 30 minutes due to 60 second tick rate limit and I had to make a decision quickly since we just had the public launch. A friend of ours who ran an SMP on shockbyte recommended them to us. It's handled our setup so far, but the consistent tick delay is bugging me. GC is running every 20 seconds (drops to 5g, crawls up to 13g, GC happens). I'm seeing warnings in the console of 40 ticks behind once every 30 seconds to 1 minute, with occasional spikes up to 150 and it crawls back down over a few minutes. 90% of the time it's exactly 40. I'm seeing this behavior whether there are 5 people on or 12 people on. Sometimes it'll go 10 minutes without any warnings though.

I'm going install spark later to see if I can figure out what's going on, but thought I'd provide these details here to see if anything obvious jumped out at the professionals here 😉 Hopefully my brain can parse the information spark gives me. I guess my main questions for now is: Should GC be running every 20 seconds and going from 5g ram usage up to 13g every time? That makes me think a mod or two could be misbehaving, but it could just be normal minecraft behavior - I have no clue. Also, is 16GB overkill for our setup? Shockbytes marketing states this config should support 60+ people with "many plugins".

Thanks!