Hi,
I can’t see the Lenovo Tab M11 among the suggested devices, so here it comes 
Before a dedicated ROM, could someone tell me whether any alternative exists ? …e.g. using e/OS/ build for Lenovo Tab M10, which should be quite similar ? or any Lenovo-generic build ?
Regards,
JC
there’s this prior request
as there is no dedicated image, you could try a GSI (generic system image). An update to the official version is still in the works, but users have a go at it themselves, see the gsi tag - Topics tagged gsi
@jcbss Lenovo Tab M11
TB330FU | Mediatek MT6769H Helio G88
My Android Tablet with MediaTek MT6789 Helio G99 SoC supports Project Treble (arm64 / A/B-Device / Seamless Upgrades / Dynamic Partitions) and runs perfectly with iodéOS GSI 5.8 (A14) including OTA update support.
As long as no comparable /e/OS-T (U) GSI is available, the iodéOS GSI is an excellent alternative.