I have experienced rth being interrupted because I left a 200ft geo zone and ascended. Upon return the drone hit the lower altitude restriction and just stopped. I am trying to learn if the new rth will allow the mavic 3 to descend to avoid a dji altitude geo zone.

As far as I know there is nothing you can do other then lower the drone manually. If you don't it will idle in place until battery is low and land.

I nearly lost my Mavic 2 during RTH when it hit a GEO zone (altitude) no way through them, either reduce altitude or go around the side of one, the Mavic 3 will be the exact same, the drone will act like there is an invisible wall in front of it, just stops, or slowly drifts to left or right until battery runs out. Mad thing was that the drone was actually only 100ft AGL when it hit the GEO zone, but thought it was 600ft+ due to taking off at 0 ft here but climbing up a hill less than a mile from here took it over the gEO zone on RTH.

Tony64 Posted at 2-27 23:00
I nearly lost my Mavic 2 during RTH when it hit a GEO zone (altitude) no way through them, either reduce altitude or go around the side of one, the Mavic 3 will be the exact same, the drone will act like there is an invisible wall in front of it, just stops, or slowly drifts to left or right until battery runs out. Mad thing was that the drone was actually only 100ft AGL when it hit the GEO zone, but thought it was 600ft+ due to taking off at 0 ft here but climbing up a hill less than a mile from here took it over the gEO zone on RTH.

... a terrible idea!     

Tony64 Posted at 2-27 23:00
I nearly lost my Mavic 2 during RTH when it hit a GEO zone (altitude) no way through them, either reduce altitude or go around the side of one, the Mavic 3 will be the exact same, the drone will act like there is an invisible wall in front of it, just stops, or slowly drifts to left or right until battery runs out. Mad thing was that the drone was actually only 100ft AGL when it hit the GEO zone, but thought it was 600ft+ due to taking off at 0 ft here but climbing up a hill less than a mile from here took it over the gEO zone on RTH.

I think you might be right, but the reason I ask is because the Mavic 3 offers a straight line RTH which uses the drones sensors to get home safely without need to ascend. I wondered if it would be smart enough to avoid geo zones as well..  I turned off this feature and prefer the old fashion RTH that ascends to a preset altitude before returning.

It might try find a way but I would be more worried that it could clip a thin branch or worse power cable or telephone cable while doing so, as we know the straight line RTH avoids these problems once it gets to its set altitude over all of them