weird situation with dryer vent

[Ron Singh]

Closed this sfr property couple weeks back, noticed the dryer was taking a lot of time to dry, so checked the vent it was clogged badly.

cleaned with vent with vent cleaning brush, end to end.

when I pushed the brused from outside point to inside, I can see the brush inside, so its clear.

can't confirm same thing other way around, as its hard to see from outside and there is not enough space to put the hand inside to check.

the weird part is when I connect the dryer, I feel only less than 5% of air coming outside. when I run dryer without connecting to vent it blows air normally. guessing the most of air is venting in crawl space from a leak or something, is it safety concern? would home warranty cover it (not sure if they would go in crawl space to fix vent if there is any issue)

vent has atleast 3, 90 degree turns. and goes through crawl space, guessing one of the connector might have gap or might be loose.

any pointers or suggestions ?