I’ve been out of the loop on games for a while but ReactOS may be worth a look.

The 1st ½ of your comment sounds accurate. But…

And also in Foss there are highly opinionated software where the devs completely ignore users, ban them from GitHub when they post issues,

Right, but to be clear non-free s/w is worse - you can’t even reach the devs, generally, and there is no public bug tracker. FOSS is an improvement in this regard because at least there is a reasonable nuclear option (forking). The nuclear option for non-free software is writing it yourself from scratch.

That all sounds accurate enough to me… but thought I should comment on this:

However - in larger enterprises there’s so much more, you get the whole SDL maturity thing going - money is invested into raising the quality of the whole development lifecycle and you get things like code reviews, architects, product planning, external security testing etc. Things that cost time, money and resources.

It should be mentioned that many see testing as a cost, but in fact testing is a cost savings. In most situations, you only spend some money on testing in order to dodge a bigger cost: customers getting burnt in a costly way that backfires on the supplier. Apart from safety-critical products, this is the only business justification to test. Yet when budgets get tightened, one of the first cuts many companies make is testing – which is foolish assuming they are doing testing right (in a way that saves money by catching bugs early).

Since the common/general case with FOSS projects is there is no income that’s attached to a quality expectation (thus testing generates no cost savings) - the users are part of the QA process as free labor, in effect :)