Good sample size for stats

Good day everyone, I’m interested in the answer to the question: what is good sample size for poker stat in NLH (in Hud or PopUp)? I'm interested especially in HU NL cash, but probably in 6-max cash or tournaments number will be the same. By "good sample size" i mean that sample sizes with low average deviation, not more than 5% (of course lower will be better), so using that sample size i can say that that if specific stat on player is deviating more than on 5%, i can be sure that this player is deviating in this spot. For example, good cbet % in SRP HU will be 65%, so if i have necessary number of samples on player and i see his stat "Flop Cb in SRP" not between 60-70% i can guess that probably this player is under/over Cbets flop.

My initial thoughts was that 100 sample sizes is good, but that's just only my own feelings. I was trying to find info on that question in the internet and i find some article (whose content make a lot of sense for me) in which author was writing that 30+ sample sizes will be perfect, but just for looking for extreme deviations. For example if Flop CB stat was very high (28/30=93%) or very low (4/30=13%), that`s probably already say that opponent is deviating in that spot (perfect is 20/30=65%), but if it's stat was around 50% (15/30) or 75% (23/30) that's probably don't say anything, because of deviation using that sample. So using this info we can make a conclusion that the more sample size we use then the less will be the deviation %, as in these example with 30 sample sizes deviation % can be +-15% and for sample sizes that we're finding, let's for example it will be 100 samples, deviation will be +-5%. But these numbers of deviations are just examples and not saying that actually especially for 30 samples deviations will be +-15% and for 100 5%.

So how can we find good sample size with dev. 5% or lower ? Maybe there is some math formula that can calculate this? I was trying to find these but all that i find it's calculator which calculates sample size for people who completed the survey using population size, confidence level % and margin error % and some articles about this. But probably that's unsuitable or i just don't understand how to use it in our case.
Maybe somebody already know the answer what is good sample size and/or how to calculate it, or just have thoughts about it? I would be grateful for any answers or thoughts, everything will be interesting to read!