Rigid duct is almost always better than flexible as you get more air movement through smooth-walled duct, it is less likely to build up a lint coating inside, and it is less likely to get physically damaged. The main issue is getting all the connections in place and sealed properly. I wouldn't worry too much about the weight of the ducting. I would just want to secure it to the wall with a clamp or a band so it doesn't vibrate and loosen the connection.

If you use pop rivets to fasten the duct sections together, then tape them with metal foil tape the joints are not going to come apart.

I usually use a clamp only on the attachment to the dryer, with tape under the clamp.

It is not a big deal to remove the clamp and cut the tape when you need to clean out and inspect the line.

Make sure to assemble the duct sections in the correct direction.
The male sections go inside the female sections in the direction of air flow.