Satoshi Nakamoto may have intentionally slowed Bitcoin adoption early on.
Yes, but probably not in a way you think. It was true, but related to mining:
We should have a gentleman's agreement to postpone the GPU arms race as long as we can for the good of the network. It's much easer to get new users up to speed if they don't have to worry about GPU drivers and compatibility. It's nice how anyone with just a CPU can compete fairly equally right now.
See? It was possible to generate more coins with GPUs, but he wanted to slow things down, because then, more CPU users could mine their coins directly. And you can also confirm it, if you compare "prenet" version, shared in 2008, with the first official one: it required 20-bit blocks for testnet, and 40-bit blocks for mainnet (which is why the Genesis Block has more than 40 leading zero bits), but he lowered that from 40-bit to 32-bit, just to make CPU mining easier.
And if you compare block times, you can also see some artifacts from prenet, because the time between blocks was more like 15 minutes, instead of 10 minutes.
Prior to version 0.3 there was no coded limit. Doesn't mean there was no constraint though.
There were other limits. P2P message size was limited to 32 MiB (and still is, by the way), even if you ignore database locks, and other limits like that.
And he later added that it could be increased through a softfork as the need arises
At that time, people thought mainly about hard forks. When it comes to soft-forks, they were invented much later.
to keep the chain's weight under control down the line
There was no such thing as "block weight" before Segwit in 2017, it was only "block size".