Tempo detection with various time signatures

I use Cubase 11 Pro with Windows 10.
I have an audio track which is very poor in keeping tempo. On top of that, the track also has changes in time signatures.
When I try to detect tempo. Cubase manage to keep up when detecting 4/4 and 2/4 signatures, but when changing to 1/3 for one bar, and then to 6/8, it cannot follow, and I cannot get it to mark the down note in the first 6/8 bar . Later in the 6/8 section it picks up, but I cannot get the start of that section right.
Anyone have a smooth trick to work around this?
Thnx, Pal