It can segment traffic by people (you record which MAC is who, segment away by theme, etc), host a custom DNS server very well, has nice firewalling features and there s no mandatory cloud account. I ve made a few custom scripts for it, and its linux base is good enough (old kernel a little bit). I paid around 300 USD for it I think, for 2 of them, and it's the best router I ever had, OpenWRT included.

The only thing I miss from openwrt is the custom vlan joining on optic fiber relay you can do with them to bypass your ISP fiber modem and just use an optical to eth converter. But that's not a huge overhead these days. Doubled the speed when the ISP's crappy boxes couldnt cool well enough for 500Mbps 10 years ago :D

The big advantage, for me, of Synology routers, over OpenWRT and its alternatives (I rmb one called Tomato something) is that it's so much clearer and easier to use quickly and climb from there. With OpenWRT in my old memories you were thrown in a discouraging mess that made me struggle a bit to find simple features (but it has them all).