The Power Vent may well be the best solution.
Sounds like you already decided on getting one.
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I like to go thru the REVIEWS on Amazon.
Some may be fake, but the Negative ones give you a heads up on any weak areas.
Check (I'm sure you do) the Lint Trap in Dryer. Clean after each use.
Also check - Once a year I pull the 'front' off of Dryer and vacuum around the Fan Blades.
It's amazing how much lint builds up besides just the Lint Trap.
Also check that the Vent Pipe is CLEAN.
With a longer run, you might have more lint build-up as compared to shorter run.
Sometimes I see clumps of lint outside underneath the vent exit (10 Ft. run).
As someone else said, is your Washing Machine spinning the cloths enough to remove excess water ? ? ?
If you have to add an electrical outlet for the power vent, know your Electrical Codes.
Only creates future problems if not followed.
Lastly, if your venting is not sealed correctly, you may be exposed to Carbon Monoxide (the Silent Killer).
I knew someone who died from that (heater in his garage).
If in doubt, install a Carbon Monoxide Detector in the area.
When I had a new Furnace install, they hard-wired a Detector in for me (Battery operated would be just as good).
Their idea, and a great one.