It really depends what your demands are regarding WiFi.
If you can live with mediocre WiFi performance (for now), then use LEDE. You can build everything that is on the original Omega FW that way, except for the wifi driver. Onion uses a proprietary driver they can't publish, stock LEDE uses the fully open sourced, but not yet fully fine tuned, mt76 driver.
For all of my Omega2 based applications I built my own distro / FW image from LEDE, tailored to the use case. There is a learning curve to LEDE, but once you get a feel for it, it's a really nicely organized distro builder for tiny platforms.
If you want to get something as close as possible to original Onion FW, then you can start with their LEDE tree which is finally publicly available.