Separate NAS and homelab server or combo?

I want to build a DIY NAS for home media storage, backups, etc... with TrueNAS Core, but I also want to run some VMs and have a home lab. I am a software developer, so I'd like to host some personal web apps as well and set up a VPN for example.

I just can't decide whether I should build a NAS and a server separately, or just build a big ass server which can do both and for example uses Proxmox with a TrueNAS VM. Every time I start selecting components I either drift to optimizing towards a home server or back down to just a NAS with a slimmer form factor. The trade-offs seem hard to balance.

I know everyone's use case is different, but are there any obvious pros/cons to building one big NAS-homelab versus separate NAS and homelab PCs? What do you run yourself and why?