Upgrade i7 to i9?

Ok I also highly suggest AMD, but I will give you some reasons why:

First off multithreading, AMD trashes intel when it comes to multithreading performance, in simple terms this means AMD will be far better at anything rendering, or editing.
Gaming, intel just barely wins with their latest release, however the AMD cpu that it just barely beat is a few hundred $ cheaper, which leads into...
Price.... just..... intel overcharges the hell out of their CPUs for little performance increase, case and point they were able to slash their prices in half and still make a profit.... and they are still more expensive then the amd counterpart. Example: (in USD) both 16 core cpus btw. ryzen 9 3950x : $710, intel i9-9960X: $2980. However that is last gen, their current gen is an 18 core i9 10980XE: $3,000. Prices are from newegg btw. (ryzen 9 3950x still beats the 18 core in overall performance btw)

Now I doubt you are going to go the highest tier so here is pricing for 10 core intel, to 8 core and 12 core ryzen:
Intel core i9, 10900/x (10 core) | Ryzen 7 3700x/3800x (8 core) | Ryzen 9 3900x
$950/$993 | $295/$329 | $420 (blaze it)

So if price alone isn't a good enough reason, the performance superiority in addition to being cheaper should be. Is how AMD has been taking a huge chunk of previously intel dominated market, to the point where dell has signed a deal to now make amd cpu computers (which they were pretty much only intel for the longest time).

Although really depends on how much money you want to waste and if brand loyalty is worth that much to you. Like if you will only ever game then go intel, they do still have the better performance.... although you could go threadripper.... which I am sure would be far superior..... and around the same price... if you want 32 cores that is.

But the biggest thing you might want to check is compatibility, because upgrading to AMD will require a new motherboard (200-500 depending on how good you want it to be), and possibly cpu cooler. which itself might end up being similar in price to just getting the intel cpu. although you would also want to make sure the intel cpu won't require the same.

But honestly I would make the move to AMD, as their chiplet design is superior to the old design that intel still uses. As for the AMD graphics card you bought, which one was it?

As for the comment about AMD always being better than intel.... that wasn't true until 3rd gen ryzen, 2nd gen gave intel a run for their money in cost efficiency, however for the same performance you would be going threadripper, with 3rd gen the ryzen 9 it has the specs of the previous base level threadripper. and was the first time AMD beat intel in gaming. with intel taking back that title with their latest but costing you the price of a new computer.

Long comment I know, but wanted to be properly informative. Linus did a good video on 3rd gen ryzen if you want to know more. And he is notoriously intel biased... well was. Although you might want to wait until the end of this year, since both intel and AMD are releasing new CPUs. and also GPUs from Amd and Nvidia, which since I have now read your comment that you mostly game and stream, would be the better place to spend you money. and I would also suggest you look at possibly going amd again, as their new GPUs are using similar architecture as their CPU, (the chiplet design), and they will also have ray-tracing if that matters to you.