Hardware recommendation

Hello, I would like to start with this service for personal use and expand it to rent, I am vfx artist with houdini, I plan to make a network of servers locally, currently, I have 3 computers with 32gb/64 ram and 14 gpus, I would like to know what would be the way to rent that power with different programs, whether to buy servers with xeons or i7,i9 etc… what difference do they have so they can manage better as nodes ?

For the deadline server I have thought to put it on this server, HDD or SSD ? https://www.give1life.com/dell-r620-2x-e5-2640-64gb-4x600gb-sas-10k-h310-4x-caddy-4x1gb-2psu-2/

Another server like this would be only for rendering by cpu, I do not know if it is something old-fashioned.

Finally the GPUS, I have been thinking about buying different motherboards with their 64GBS and separate them into several nodes or in a motherboard I have 8 1660s connected by risers, I do not know if I should better put them all in a server rack to work better can you help me ? D Thanks.