Testers like Ideal VDV let you check it undisturbed in the wall. Use a patch cable that you verify known good first using the same tester. It will tell you if you have no choice but to re-terminate but won’t tell you which end requires re-termination.

Other similar testers from Klein or Fluke. Ideal can be bought at Home Depot in USA or elsewhere.

$.08+ /kwh USD here, and I still opted for the lowest powered 24x7 network gear feasible. Once I calculated cost/watt/year, the economics of doing lower power became real even for lower costs like mine.

Good choices, OP!!!