Care to help a newbie in need?

I am really new to the DIY eskate world i got this guy in my area that makes them, make one for me because i was scared to screw up something so expensive, so i have 2x 1500W motors connected to my esc and a 23Ah 104p battery (40x LG 5540 mah per cell), the problem im facing is that im kinda fat so im having trouble riding uphill, and the place i live is mainly in the mountain area, as soon as i climb about 100/200 meters the board stops and the heatysink on the esc gets warm, i already ruined one battery this way and i had to get a new one but im super scared to ruin this one too because they are expensive for me, we tried a load reduction with 72T pulleys and shorter belts and i can go longer without it stopping espoecially if i go slower but it still stops and the battery and heatsing still get warm, i dont have a remote with a screen that shows battery temperature and im scared not to burn the battery, any tips or solutions?

you can use a lower KV motor to get higher torque. For example: In Stock! MTO6374-90-HA/ MTO6374-90-HA-C Maytech Sensored 6374 90KV 18 – MICHOBBY.COM