Then the question is why the BS value is random, not the faster the computing power, the faster the record, and some people have not updated it for many days at all, and there is the so-called luck of changing wallets

There is a lot of confusion that one needs to clear before understanding how all of this works, it's best to start with some basic definitions of key words, those key works would:
1- Random:
an event/process that is not and cannot be made exact and, consequently, whose outcome cannot be predicted, e.g., the sum of the numbers on two rolled dice.
Source:https://pages.jh.edu/virtlab/course-info/ei/notes/uncertainty_notes.pdf
2. Probability:
an estimate of the likelihood that a random event will produce a certain outcome.
Soruce:https://pages.jh.edu/virtlab/course-info/ei/notes/uncertainty_notes.pdf
Back you to question, the likelihood aka probability for a faster hashrate to get a higher share is HIGHER than that slower hashrate, but given that those are random events you can't be too sure that this will be the case unless measured against infinity, probably in a vacuum where nothing else could affect the probability of the events.
If you were to check the best share of two random miners, one with 10th and another with 100th, it's likely that the 100th will have a larger best share, it isn't exactly 50/50, because if you were to check 100 miners with 10th vs 100 miners with 100th you are a lot more likely to find higher best shares on the second group, if you check a sample of 1000 each, it's even more likely that the second group will have a better average best share, 1 million is even better, infinity is best (although one could argue that infinity doesn't exist in the first place

).
Thinking about mining and shares could be confusing to most people, it would be better to just imagine a scenario where you go hunting with another person, both of you are blindfolded, and it's 3am, your gun fires 100 bullets a minute, his does 200 bullets a minute, every now and then a rabbit runs in front of you ( you can't see it, so skills here are ignored), so the two of you randomly fire 300 bullets at those poor rabbits, it's very possible that you could hit more rabbits than him in the first minute (Luck), but if you both keep shooting at the same pace for 1 hour, it's more likely that he would kill double the number of rabbits given that he takes more shots than you do (Probability).
Best share in our hunting example is like the "nearest shot to a rabbit you had so far" pretty meaningless when you are blindingly shooting at moving rabbits, it doesn't matter if your last shot was only 1cm or 1m away from the rabbit head, the rabbit is moving, your hands are shaking, it means exactly nothing because the following shots will not depend on that and are not affected by it or by any event that happened in the past, every shot you take is a completely independent event and has the exact same chances of hitting a rabbit as any other bullet that you fired or may fire in the future.
If block share is 1000, and a 1th miner has best share of 999 while 10th miner has only 10 best share, it doesn't change the fact that the second miners is 10 times more likely to hit a block than the first one.
Thanks for the careful explanation of the seniors, so sometimes I think about other aspects, the long-term shooting probability of self-owned equipment, and the so-called high and low computing power extended to renting multiple equipment, there is also the so-called continuous output and can only be rented for 24 hours, and others There are many factors such as the luck of the output of the large and small mining pools, which have become the scientific knowledge and value of people's continuous efforts