I think PHP is way better now than it used to be. Learn PHP 8 and you are good to go.
I have no clue what the future brings for PHP, but PHP 8 is definitely a good start, and we should put PHP 5 to rest.
PHP 10 might not be that different from PHP 8 for all I know.
We do not know if there will be "constant change". Out of curiosity, what programming language do you use that you also love?
FWIW, if by "constant change" you mean improvements or bug fixes, then I do not see why we should not have those. I do not even mind breaking backwards compatibility if the reasons for breaking justifies it, but it has to be a really good reason.