I don’t see how they’d be easier than midi.
You may find this site interesting: https://folkrnn.org/tune/119105 Thing is tabs and other kinds of notation only capture a small part of the composition, often just the melody. So to generate "real" polyphonic music you need other kinds of data.
Update: looks like some papers got into it last year:
Rock Guitar Tablature Generation via Natural Language Processing: https://arxiv.org/pdf/2301.05295
GTR-CTRL: Instrument and Genre Conditioning for Guitar-Focused Music Generation with Transformers: https://arxiv.org/abs/2302.05393