Plastic flexies have been prohibited by fire code for dryers for many years.
The metal flex must be limited to the shortest length necessary to connect from the machine to the hard pipe. Those snorkel devices are OK if you need it. A little pricey.
All seams on a dryer run should be taped with foile tape. Screws or rivets are probited, as they will be a lint grabber on the inside.
The manufacturers installation manual for your dryer gives the limits on rise, length, and # of elbows. What you describe probably falls within limits, but long runs definitely affect the efficiency of the dryer. Heavy towels/jeans etc especially take longer, thus more $$$.
You might be well served to install an inline duct booster fan. They are available....google fantech for one manufacturer.