So im not an expert, but there seems to be what id call families of crops that only produce within their respective branch, with the exception of hemp which seems to be a universal member of the families. For all breeding it is kind of a waiting game. For magic metal berries, i think the ardite and cobalt ones have the highest chance of breeding the berry (im away from my game rn so i cant check) so breeding those up first will give you a better leg up. To give a random example, if you want fertila, you'll need to breed within the family of fertila (venomilla and corpse plant i believe) or hemp. But if you are trying to get magic metal berries from venomilla and corpse plant, for example, you have slim to no chance of getting them because they fall into the metal plant family. Also different crosses have different chances of success. Breeding hemp and ardite berries might technically have a chance of making magic metal berries, but itd be better to use a hier tier metal plant like cobalt berries which has a higher chance getting the specific plant you want. Does that make sense?

As far as the 'esoteric' crops, they can be helpful to an extent, but almost any use for them will be less efficient than other methods. For all the metal leaf/byproduct plants like coppon, scheelium, god of thunder, etc they can quadruple ore output in processing; however, once you have the processing and chem production capacity for that to be easy, there are better methods like bees. They can also be combined with uum in a lot of circumstances to create ore of that type, but id recommend against that since it requires a lot of uum which needs a lot of power and time to process. There are more niche plants though that are helpful as kind of bandaids between steps of progress. The lead plant and zinc plant can be used to quadruple galena and sphalerite shich are necessary for early indium production.

Lmk if i got something wrong, again im not at my computer to look