I'm not sure where you saw that unraid has a limit of 30 drives. With the Pro license, you can have unlimited drives which seem like at least one of the requirements you are needing for your build and future expandability. For reference, I got that information directly from the unraid Wikipedia page. JDM is going to have one of the most comprehensive resources. Also, you need to understand that serverbuilds.net is a product of JDM_WAAAT which includes numerous build guides with cpu comparisons and motherboard options and ram recommendations. Not to mention countless choices for cases/chassis for all the hardware and the best fans and heatsinks for your specific build and use case. There are also options for DAS setups if you need one.

I speak from personal experience that the community that JDM_WAAAT has built is fantastic. I used an older guide for a dual cpu xeon NAS/plex server and have been very happy with it. Join us over on the serverbuilds discord and ask questions to get an idea of what is right for you. I think you will be glad you did.