Will she be ok

Hello With your burn spreading to more than just the tips is a good sign there's more happening than just a typical nute burn. Since you're growing in soil I'd suggest raising your ph up to at least 6.4-6.6 having it down at 6 will give a higher possibility of locking out calcium which needs 6.2 or higher. I think running consistently a touch low will run the risk of slowing her down like you mentioned. I'd go through with a higher phd water and give it a good soak, check the runoff while you're doing it and then you'll probably be fine to add in the pk shortly afterwards. Happy flowering.✌️