"Buy once, cry once" — spend more upfront for something you will not outgrow — is sound advice for a lot of purchases. For a beginner's first bass amp, I think it is a trap, and the more expensive route can actually slow you down. There is a real case for buying a modest, even slightly worse amp on purpose at the start.
The problem a big amp creates for a beginner
A powerful amp is loud, and loudness is the enemy of practice for someone who lives with other people. An amp you are afraid to turn on is an amp you do not practise with. A small practice amp — or even a tiny headphone amp — gets played, because it fits a bedroom, a flat, a late evening. The best amp for a beginner is the one that lowers the friction to picking the instrument up, and friction, not wattage, is what kills beginners.
Why "you'll outgrow it" is fine
You will outgrow a starter amp, and that is the plan, not the failure. By the time you do, you will know whether you want warmth or punch, whether you play at home or in a room with a drummer, whether you need volume at all. That knowledge makes the second purchase a good one. Buying the "forever" amp first just means buying blind and hoping.
The takeaway
Start with something cheap and small enough to actually use every day. Let it lower the barrier to playing, let your taste form, and upgrade when you have real reasons. The worse amp, bought on purpose, often produces a better player — because it gets played, and playing is the only thing that was ever going to make you good.