Apologies in advance if this is not to your liking.
Let’s just say that link aggregation is messy. I have it on my old server, a quad connection to a GS1900 or something like that. It took a lot of trial and error. I did it mostly for fun, I had the hardware, my homelab did not really benefit from it and I knew that beforehand. Please don’t take this the wrong way, but based on your questions it is not entirely obvious that you know if link aggregation will benefit you enough to warrant the trouble. Just switching to the Intel NIC from the Realtek NIC would be nice now that you have it.
Why do you want link aggregation? Which problem/problems do you think it will solve? What will it improve?
In the meantime, if you insist on going through with it — How about getting a free trial of some streaming service with content your partner is happy with to buy some time to tinker with the switch and your server?
If you make a backup of the configuration you can go back to the current state of affairs with ease, no borking the whole thing for days. If you can’t get it working in 20 minutes, just revert to the previous configuration and use what you’ve learned to prepare for a new attempt some other time.
If you can use GUI mode on the server things should go smoother during trial and error.