No bonus.
Little to no benefits.
Solution architects are absent from their teams and put their responsibilities on middleweight developers.
The way to progress at this company is to do as little work as possible and just focus on your personal development. Take it from the solution architects directly, as they spend most of their time reading developer articles and posting them in Slack during work hours rather than doing the work they are meant to be doing, to the extent that they don't reply to direct messages.
Solution architects are responsible for hiring lead developers even though they have no idea what lead developer's responsibilities are.
Lead developers are interviewed as though they are applying for solution architect positions. If you apply for a lead front end role then expect to be asked backend/architectural questions and to do backend test tasks.