Cracked lemon tree trunk/branches

jakfruit etiquette says...
Its called gummosis. It can be caused by pest infestation stress. In severe cases it could be phytophora. In your area that may be likely.
Sometimes sun exposure will cause cracking and weeping on one side.
Borers can also kick this off, can you see any exit holes ?? usually pencil size holes.
This can let rot inside the trunk and roots,
Copper oxychloride could be painted as a paste over the cracks all over the affected trunk. It will wash off in the rain. I use some powdered milk into the paste to help it stick longer.
A fungicide could help to control Phytophora.
Phos acid could be used, its a simple chemical fungicide, safer to use than other fungicides ???
https://www.bunnings.com.au/yates-500ml-anti-rot-fungicide_p2961096?store=6156&gclid=Cj0KCQiAoNWOBhCwARIsAAiHnEjAsBwUNN4-A_MLiTbtOWCiT_wqH21vd3ImsSol5sPmhDTLZP2XfOgaAqbuEALw_wcB&gclsrc=aw.ds
Another help would be increase the biological activity around the roots, compost, manure tea etc.
Composted chicken manure has been used to control root rot https://www.daf.qld.gov.au/__data/assets/pdf_file/0020/72263/factsheet-citrus-and-wet-weather.pdf

There is a warning about not using the copper and the Phos acid at the same time.