Smart TVs run a full operating system on very modest hardware. Storage is measured in a few gigabytes, and once it fills, apps fail to update or refuse to open.
Support windows are short too. Streaming services drop older TV platforms after a few years, so an app can disappear from the store entirely while the TV keeps working perfectly for everything else.
Crashes on start-up usually mean a cached data problem. TVs rarely clear their own caches, so a corrupted file can persist through dozens of standby cycles.
The practical answer for an older set is an external streaming stick. It is cheaper than a new television and updates for far longer.