Using an old router as a switch?

I'm using an old router as a switch, and wanted to know how advisable this is.

While wifi is now provided by a couple of decent APs, I'm still using an old TP Link router (TL-WR1043ND) to act as a switch in one part of the house. I had been using a newer router for this duty until today, but had significant network problems (both wired and wireless) that went away after I took this router out of the equation.

I've done the standard things I'm aware of like disabling the DHCP server, assigning it a different IP address on the same subnet and disabling wifi, but I'm worried I'll end up with similar problems. A Google search shows some suggesting disabling NAT, but I don't have any such ability to do so on this router. Could this cause a problem?

Essentially, I'm looking to create a reliable and stable network - both wired and wireless - so happy to replace this router with a dedicated switch if it's advisable to do so. If so, do I need to get something fancy, or in this case would a consumer-grade switch like this one be ok? https://www.ascent.co.nz/productspecification.aspx?itemID=375927

Many thanks