Unlikely the vSphere caching feature will help with the swap files and read operations it will do nothing for write performance increases.
Thin provisioned aren't the best for performance either, go with eager zeroed thick vmdks instead if you don't want to use RDMs in this case.
The controller in the NL36L is meh under vSphere don't expect anything major from it, you will get better performance just installing Xpenology on the NL36 itself and getting a decent server ML110/150 G6/G7 for and use that for your lab instead or the newer Microserver.
If you want a proper managed switch for your homelab get yourself a SG300-10P L3 switch
Enjoy