There is an inherent problem in cycling rainwear. Even 'breathable' fabrics such as Gore-tex will still be less breathable than not wearing anything. And lighter weight more breathable jackets will probably let more rain in...
Therefore if you're going to continue to put in the same effort with a jacket on as you do without, then I'd advise getting a saddlebag and losing the backpack at the very least.
Alternatively, slow down a bit when it rains and/or get a cape.
There is an inherent problem in cycling rainwear. Even 'breathable' fabrics such as Gore-tex will still be less breathable than not wearing anything. And lighter weight more breathable jackets will probably let more rain in...
Therefore if you're going to continue to put in the same effort with a jacket on as you do without, then I'd advise getting a saddlebag and losing the backpack at the very least.
Alternatively, slow down a bit when it rains and/or get a cape.
(sorry that's not v helpful...)