There's something called "fake PGWP extension": meaning – when you apply for an extension of PGWP, you'll be on
implied status until it's rejected (which it will – for sure). The processing time aka rejection time might be somewhere between 3 months to 5 months depending upon the backlog. It should give you enough time to figure out your queries with IRCC. However, if your ITA doesn't come through and later, after the processing time, when they reject your PGWP extension application, you'll need to stop working immediately, and restore your status as a visitor or leave the country.
*If you manage to get an ITA before your PGWP extension is rejected, you can apply for a BOWP, and wait for your PR to complete processing – I heard that it's taking about 5 to 8 months approx to complete processing PR application.
Now, as to why I'm confident that IRCC will reject your PGWP extension is because, PGWP is a once in a life time opportunity – there's no extension policies anymore. One cannot apply for an Open Work Permit either, unless they've got a positive
"Dual Intent" LMIA, or... just checkout the list below from IRCC website.
You may be eligible for an
open work permit if you
So, you can apply for a PGWP extension while baring in mind that the outcome will be a rejection, and secure an ITA before the outcome. Ultimately, this extension trick is only to buy you some time – try not to rely on it.