Active engine list issues

I use DCS on my HO scale layout with 31 MTH locos. After turning on track power the system can only find 10 to 12 locos (in the active list). I have 2 TIUs with Wi-Fi. I cannot move a loco from the inactive list to the active list. I’ve added filters on the TIU outputs and on the blocks with poor DCS signal quality. I’m considering selling this frustrating system and going to DCC. I’ve used star pattern wiring and followed Barry’s wiring recommendations. If I switch to DCC, are there changes needed in my wiring and which DCC manufacturer do you recommend? Vic 8173139579.