Short answer is yes, it is worth it. However not by much in my opinion, which is worthless because you are the only one who can tell if the gain is satisfying or a waste of money.
The GPU will perform very well with both CPUs. Overall, the PC will be faster with the i7.
Just be aware that your power demand will go up a bit, and you might need a slightly more powerfull CPU cooler.
It's really hard to gauge whether gains are marginal or good enough to be worth it. Objectively the i7 is faster, but whether your games will run any faster is harder to tell. Some games were notorious for lagging even on superb hardware.
Maybe if you describe your system specs and tell us what your gaming demands are, someone could offer a better answer. Are your games running ok or is there lag? Some games care more about CPU power anyway so the 4080 is going to be less of a factor if you improve the CPU. Other games are more sensitive to RAM latency. Etc, etc.