Bricked M8? Will pay for help

Hi i got a Htc One m8 from Tmobile(germany). s-on but rooted

I rooted it 8 months ago but since then i have no working wifi, if i turn it off i have always flash my custom rom again because of bootloop, and a lot of more problems... i even cant go to stock rom because im very confused about all infos...

is s-off via sunshine a good option ? i hesitated to pay 20 bucks for it.. i cant even read my cid because its empty when i want to read my cid..

can anyone help me? i would pay someone who help me fix my m8 ...i would be so grateful...even my local mobile phone store cant fix it..

greets from germany.