You can buy yourself a pair of old Dell servers from craigslist or eBay for a few hundred bucks. With a $200 membership to VMUG Advantage you'll get all the licences you need to build an enterprise grade cluster.
Build yourself a home lab and learn how systems work. Figure out what is really running your code. Learn how to resource optimize.
Don't end up only being able to work on webapps and small datasets that fit comfortably in the cloud.
I'm not sure if this is still valid advice. I'd just stick 64GB of memory in a desktop PC and have the home lab running on VMs.
5 years ago I left a company running loads of enterprise software and web applications for other companies in a couple of data centers. We had well over 10.000 physical machines. When I left, about 90% of the workloads were virtualized. Running on bare metal is the exception today.
Sure, its cool to have hot-swap HDDs, hot-swap PSUs, redundant network cards and a remote management board but none of that is rocket science. You can learn it in a week if needed.
Networking is a much deeper topic yet almost nobody would recommend you to set up a couple of switches and hardware firewalls in your home network. Today you expect that the hardware just works. In the real world it is extremely complicated to correctly design and run networks, but you aren't going to experience any of these problems in a home lab.
Being able to operate server-grade hardware is a nice skill. There are features in server hardware (like lights-out management, dedicated RAID controllers, etc) that you don't always get in a desktop PC.
That's been a plan of mine. Right now, my home server is just a Pi running SMB and Jellyfin, but the plan is to expand into some used hardware. Seems like used server hardware is one hell of a deal.
Build yourself a home lab and learn how systems work. Figure out what is really running your code. Learn how to resource optimize.
Don't end up only being able to work on webapps and small datasets that fit comfortably in the cloud.