Waveshare ILI9486 TFT 3.5 INCH LCD DISPLAY not working on a MKR WIFI 1010 put on a MKR2UNO adapter

The switches should be in the ICSP position.

You should connect MOSI and SCK from the 3x2 ICSP header.

In an ideal world you would switch to ICSP position and plug display straight into the MKR2UNO . However the MKR WIFI 1010 will be in the way. You need "tall" sockets on the MKR2UNO.

Personally, I would just try "stacking headers" if you have some.. Or just use individual jumper cables i.e. for 3.3V, 5V, GND, D9-D7 and ICSP pins 3,4.
8 cables is not too daunting.