I moved from the A320 to the A350 just over two years ago, and they are remarkably similar to fly (by design)! I would go so far as saying that you could hop in the A350 sim with zero training, and you would be able to operate it to a safe standard.
I've got two possible progression tracks from here: 1. gain experience on the A320 for a year, get upgraded to the A330, after two years get certified for the A350 to fly A330/A350 mixed. 2. spend years on A320, upgrade to captain, many more years, then finally upgrade to A330 as captain, then two years later A350 added.
I am planning to fly jump seat to see all the types we're flying.
Career progression in airlines is interesting - with lifestyle being so heavily influenced by seniority at most airlines, there is often a big tradeoff decision to make between lifestyle and salary.
At my current airline, the most well-trodden career progression has historically always been Short-haul FO -> Long-haul FO -> Short-haul Captain -> Long-haul Captain. Curious if this is the same at other airlines?