2 Thunderbird problems. Filters and S-L-O-W downloading.

[linux guy]

Yesterday I migrated my email activities from Evolution to Thunderbird
after my Evolution setup had been non operational for 4 months.
Painful.

Fortunately, I use gmail as my mail server, so I accessed my several
email accounts via a web browser.  Painful, but it worked.

Thunderbird is working OK, but I have 2 issues.

1.  It is taking forever to download the emails from one of my gmail
accounts.   When I Get Mail on that account, it comes back saying a
handful (8 to 20) emails are ready to download, downloads them and
then stops.  If you check again, it gets another handful and stops.
And again and again.

I have several thousand emails to download from that account.  Why
Thunderbird getting 200 emails at a time ?  Is this a gmail problem or
a Thunderbird problem ?

2.  I sort all my emails into local folders using filters.   I have
created a half dozen filters, just like I would in Evolution, but they
don't seem to run.  When I go Tools-> Message Filters-> Run Now,
nothing happens.

I have FiltaQuilla installed.

Any and all help on these issues will be greatly appreciated.

Thanks