You might want to rig up temporary shade to get it through its first summer, especially during heat waves. This is when new trees are most vulnerable. Most Avocado trees look pretty bad the first year, then they get going. Note that Avocado root systems are fibrous and need to be kept cool. So a fluffy mulch of their own fallen leaves is best. Until they can build up their own carpet of fallen leaves as they grow, mulch around the tree, keeping the mulch a few inches away from the trunk.

And you tree is really close to the fence. They get pretty big, you know.

In areas with sun and heat like SoCal, avocados can be grown as understory trees, meaning under larger trees with part shade. It could be getting too much sun.
And I agree it is way too close to the fence, grown there your neighbor will be getting half your avocados.
Can you move it so it's in more shade and has 10-15 feet around to grow?
Carla in Sac

Honestly it does look like salt damage - which is basically what you‘re referring to when you mentioned the water (using rainwater will help). It could also be sunburn as the others have said.

Add gypsum. It helps with the salt. And maybe try to water a bit less often and more deeply to leach some of the salt. You use chemical fertilizer on the lawn? That is all salt.

It does not look like sun damage. The new growth would get hit the hardest as it the most tender.