Slow upload speeds with EAP 615

Currently I have only 1 EAP-615. I was planing on getting 2 more of EAP-615 or EAP-655 but I'm questioning using TP-link EAP AP's at all?

I don't have very fast internet, been told months ago that fiber is coming but still waiting.

Below are my Internet speed tested with different configurations. All configurations provide similar performance with exception of upload speeds on EAP-615 (I don't think its connection to EAP-615 as I tested that too, last in the table.)

Anyone knows if there is explanation for this and maybe solution?

ISP Router Upload Download
Test 1 19.6 1.06
Test 2 19.6 1.05
Test 3 18.2 1.05
Synology Router (bridge mode) Upload Download
Test 1 17.2 1.06
Test 2 19.7 1.06
Test 3 19.3 1.05
TP Link AP EAP-615 Upload Download
Test 1 18.8 0.73
Test 2 19.1 0.74
Test 3 20.3 0.76
LAN from EAP-615 directly to laptop Upload Download
Test 1 20.5 1.06
Test 2 18.6 1.05
Test 3 20.2 1.06