T5610 hardware upgrades.

Hello Dell, community! Happy year to all who are reading this.

I bought my 3rd Dell computer, a T5610 Refurbished, with 2x E5-2620v2 , 8GB x 2 - 16GB of RAM , 1250 GB SSD with a K2000 in it. With a 825w PSU.

I am searching for upgrading this beast , the idea of this machine is to use it like a desktop that can game (Not to play 4k but still to play when Im very tired), compile things, and have enough space to save things and to virtualize machines. until I can use it as a homeserver..

Here are some questions:

1- Can I install a TPM 2.0 Module? (Not for installing WIndows 11 , I want only if I can install it to have fun on how it works)
2- Could I install a 6GB VIdeo Card like a 1060, 1080 ? I tested my partners RX550 Series with 2GB of ram running cyberpunk 2077 and it doesnt go playable in Ultra, but in Mid it works flawlessly but some times it gets stuck, like 1sec and goes on. (Can it be doing some type of Bottleneck?) In the case it doesnt do bottleneck can I play arround with SLI?
3- NVMe ... I cant boot from them , I know that but can I take the real speed of the NVMe Experience with an EM2-5003?
4- If I decide to upgrade the procesors ,  I have to do it in the both ways? Or i can upgrade CPU1 and then CPU2 ...?
5- Should I go for USB3 PCI card too?

And last.. how can I could squeeze the best of this computer, so it doesnt get wasted in time, and give it more years of use as a desktop.Your opinion for me is very important, and lets me learn about hardware and dell hardware. 

Im so amazed with this computer, 6 years ago I worked with UPLC Dell workstations and now I can get one for myself, So Im not giving up this machine, and buying a new gaming machine , thats no fun!.

Thanks for reading!
Cheers from SouthAmerica.