He's not yet 2 right? Given he's been napping just fine up until the last few days and never historically been super LSN I would keep offering. Push it later. Give lunch later if necessary (if LO is hungry give a snack to get to later lunchtime). I wouldn't encourage a nap drop at this age given how much developmental sleep regressions can mess with sleep. Even if you do, you will need to offer some form of quiet time. You could try down time on the sofa if you want but to be honest I feel unless you are looking at the nap really going for good (I think not just yet, but it's your call) then I would keep persevering in bed. As soon as you stop that routine I think the likelihood of successful naps plummets.
Just talk us through - what time is WU/BT right now with all these NNDs and what time are you trying for the nap. For how long? How are you doing the WIWO or whatever you are doing? Do you get the sense it's become a game/battle of wills?