I installed a new argon box with nvme and I have several questions

Tengo muchas preguntas y dudas:

-I installed with 100% success but when I do a speed test it gives me a writing speed of about 530Mb/s and a reading speed of about 850Mb/s.
the disk is 500gb brand samsung evo 980

-Another issue is that when I always transfer data from hard drives on the network to another PC, netdata tells me that I have IO Waits and it turns red warning critical,
This already happened to me before using an NVME

-I would like to know how I could now that I have the SSD to improve the performance of the jellyfin further if possible. the jellyfin in portainer I had to limit the ram to 2048gb because it wanted to suck more than 4gb

-Now that I use NVME if I want to do a clean installation of dietpi without removing the nvme from the case how could I do it.
since if I try to clone from the pendrive to the nvme that is in use with rpi-clone it will not let me

Sorry for the bad English, I’m Spanish and I’m always using a translator.
thank you.
and thanks for your patience, I’m new to raspberry and I’m learning everything I can.