It is possible the built-in Trackpad has a hardware issue, or perhaps the battery is swelling and pressing on the Trackpad which can cause tracking issues. Does the Trackpad appear to be sitting higher above the palmrest, or do you see the Bottom Case beginning to separate from the rest of the laptop around the front or side edges? If the laptop has all four feet intact, then the laptop should sit completely flat & solid on a flat smooth table surface, otherwise the battery may be slightly swollen.
You may also have a software issue or possibly some other hardware issue with a connected device which is causing the problem. To look for possible software issues run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper. If you give EtreCheck "Full Disk Access", then the report will include more information which may provide more clues.
You can also try running the Apple Diagnostics to see if any hardware issues are detected.
Edit: Try booting the laptop into Safe Mode to see if you still have the problem since Safe Mode disables most third party drivers & startup/login items.
