[acceptance] Use block times for waits/timeouts instead of hardcoding values

**Is your feature request related to a problem? Please describe.**
Currently we're hardcoding long timeouts for tests to succeed on persistent devnets.

**Describe the solution you'd like**
Use the block time to potentially calculate the timeouts.

**Describe alternatives you've considered**

**Additional context**

Start by locating the acceptance tests that hardcode long waits and timeouts for persistent devnets, then identify how the devnet block time is exposed. Define the timeout calculations around that block time and verify that the acceptance suite still succeeds on persistent devnets. Done means the relevant waits no longer rely on fixed long values.

Written by the indexing model from the issue text.