Personally i like to upgrade to what i can afford at the time, But if i can't afford what i need then i dont pull the trigger til i can.
For example if i was building a new PC today without being too specific, Id probably go with whatever top level i7/i9 was to be had, I'd also look at AMD ofc and compare between what they had similar vs intel, price vs performance and so on. 32gb RAM is pretty much the MIN id go with in a new system, A couple of times my 16gb has been seen short. Especially with new games taking a lil bit more. GPU wise, My 8GB card is sadly out of date, It was a mid to high end bridge card upon release and to be fair still holds well today, But still its bang average nowadays in terms of gaming, Which is mainly what i use my pc for, So MIN gpu ram for me going forward would be 10gb ideally 12+.
Mobo doesn't need to be top spec, But it does need to be a Z*** board if its Intel and then the equivalent for AMD, I do OC cpu/ram and without going to the crazy priced mobo's, you can get most features for a couple hundred quid(Not Dollars
).
Cooling, As i said i liked to OC, it isn't anything crazy or pushing mental numbers just because i like to do it. I run my 10700k at 5ghz since day one and i've not touched it since. Knowing that my series of i7 runs a bit hot id have went with a better air cooler, Something Noctua probably but i don't need liquid cooling personally and i don't need the faff, Albeit they're very nice looking and perform great, Just isn't what i need as id rather spend the budget else where.
M2 Drive and an SSD is essential.
Case wise, Whatever takes my fancy on the way it looks but also has to have the features i'd need/sufficient space for upgrades down the line etc.
PSU. With todays GPU wattages whatever the biggest/best was i could afford. Never cheap out on the backbone of you're system.
Albeit mostly rambling but my two cents