New UW job not working out, any advice?

I work with medical insurance in the UK with about 4 years case UW work and the company I worked 9 years for got bought out and they TUPE'd me to another company to close the pipeline business.

That dried up and I applied for an UW role at another company and have been there 7 months

I was enjoying it but now I am not, the systems are complicated and tasks like copying out paper apps and doing long GP reports take me about 2 hours so its only a matter of time before they sack me...this could happen right before xmas and I have a family and mortgage to look after.

Im on a PIP now and am going to have to work very hard to get over this but words like 'concern about my risk approach and how I assess cases' have got me thinking i'm just not good enough for this company and I'm not sure things will change for the better so should I save both our time and hassle and step away?

I am of course worried this might happen again and i'll end up just moving around because right now I feel like everything I know is wrong but that could just be the fact this place has so many complicated guidelines and my last place had a much more user friendly system and UW app engine which helped me a lot

Has anyone else felt like this?

If not, what would you do? Stick with it or apply elsewhere?