Edit: I want to thank eveyone for their generous help. I ended up getting the Advent X groupset and got it installed. Although I still have some tweaking left.

I have a Triban RC100 and am looking to convert it to 11 speed. Seeing as I had a budget, I found Sensah Srx Pro and Shimano Rs100 wheels. That was when I got stuck.

I am looking to have some lower gears that would work offroad so what cassette would be compatible?

Thank you for your help.