Missing Feature or User Error?

If each instrument was isolated on a separate it would be possible to time-shift one instrument, e.g. edit one off drumbeat,
but if the instruments are all on the same track then shifting one but not the rest is impossible.

Simultaneous multitrack recording apparently is possible on Audacity … Multitrack on a Budget, TASCAM US-1800:

But even then you’d have to ensure each musician’s contribution was isolated , and didn’t include the sound of other musicians if you wanted to time-shift one instrument.

Without additional hardware you could you record each instrument separately asynchronously, (one at a time), but that’s not a live ensemble performance.