How long can it take for a PIP review decisions

I was sent a PIP review form to fill in back in May 2021 but have not yet received anything back other than receiving a text message in August 2021 stating the form has been received and would be in contact if further information is required or an assessment is a need, I called them in December 2021 of which they confirmed they received my forms on 29th May 2021, I asked how long It could take for a decision and they advised they could not tell me as they are running behind with forms due to the pandemic. What is the longest time someone has waited to receive confirmation if their PIP is extended or being stopped, is 35 weeks and counting a normal length of time.

Thank you, I will certainly try asking again. My condition has got a lot worse since my last claim 4 years and I have sent them all relevant evidence from professionals. On my previous claim they did not award me any points for mobility due to my sever mental health which causes psychological distress at all times and when going out so I once again explain this in the mobility section.