Macbook pro trackpad erratic/not responsive

Hello,

I would like to start with stating that the problem is not caused by moisture and I did follow the advices available online, with no success.

For the past few months my MBP Early 2011 trackpad has been acting strange. Sometimes it is impossible to use the laptop without USB mouse.

From time to time the problem goes away with restarting the computer but usually comes back after some time.

The cursor is not responsive, keeps jumping around, click is not working, the problem goes away when USB mouse is attached.

I've been trying to book an appointment at my local Apple store (London) but with the new policy it is ridiculously impossible to find available appointments.

This is driving me crazy as I can't use my laptop when travelling or in bed anymore unless I keep it on the flat surface and use the mouse.

Is there any way I could fix it myself or do I need to get a new trackpad and have it replaced by Apple? It might not be worth a hassle as my laptop is pretty slow and old anyways.

Thank you and sorry for the messy question, this problem frustrates me every time it happens!