100% worth checking but yep, each game is different in what represents the best value so for any gacha, always do some research on it for sure before spending! 
Sword of Convallaria
$5 subscription that gives 300 luxite (their jades/gem equivalent) immediately and then 80 per day for 30 days. Total of 2700 luxite. Pulls cost 150 so it's 18 pulls.
Honkai Star Rail
£5 subscription that gives 300 paid jades and then 90 normal jades per day for 30 days. So 2700 normal and 300 paid ones (these can be converted to normal jades 1:1 but can't go back the other way). Summons are 160 jades so it's 18.75 pulls if you converted the paid jades over.
Nikke
$5 subscription that gives 330 paid gems (jade/lux equivalent) and then 100 per day for 30 days. 3330 total but their pulls are 300 each, so 11.1 summons equivalent.
So each are 30 days, and they all have some kind of upfront thing, and the price seems to be around £5/$5 pretty consistently as well. Nikke one looks like the worst value but I find them pretty generous on rewards and bonus things you can get so they make up for it elsewhere.
Nikke battle pass isn't really worth it unless you want the skin it comes with, as it's about £20 and the skin is unobtainable elsewhere. HSR and SOC both have cheaper battle passes that are like £8 ish and don't give as much, but some extra resources and a few additional pulls each.
Core game on SOC is fun but I absolutely hate the RNG elements of the gear farming as there are 3 different gacha mechanics for boosting character power up so not sure I'll continue it long term, going to give it a couple of months more see how I feel.
Nikke and HSR are better here, and both offer ways to gear up where you can influence the rolling to some degree. HSR in particular with it's latest patch notes is introducing some better quality of life for relic and planar set farming.
