Honestly, the difference these days between CPU models in performance for single-threaded stuff, which is the bottleneck for most everything aside from some games that will use all threads, just isn’t all that high.

I tend to get high end CPUs these days because the CPU market isn’t advancing all that quickly in performance these days either, so you’re not buying something that you need to replace in short order. But you gotta consider what the tradeoff is.

The highest end CPU there is the 9950X3D. The lowest end CPU is the 9900X.

https://www.cpubenchmark.net/compare/6549vs6171/AMD-Ryzen-9-9950X3D-vs-AMD-Ryzen-9-9900X

You say that the 9900X costs 25% less.

In the above benchmark, it performs 1.1% worse in single-threaded performance, and 22.2% worse in a multithreaded performance — this is a synthetic test that ties up all cores.

If you’re, say, web-browsing or doing the great majority of tasks, you’re probably going to be a lot closer to being bound by the single-threaded difference – you aren’t likely to be saturating all cores.

Even most games won’t tie up all cores.

If you’re doing video editing, that might.

But the difference just isn’t all that large for most things. Unless you intend to be doing a great deal of the few things that’ll actually tie up all your cores, the CPUs will probably perform about the same. If the cost difference is important to you, probably won’t much hurt to go with the less expensive CPU.