How much processing power should you assume an attacker has? The answer to this question says that you should assume an attacker can do one billion operations per second: Key Size for Symmetric Homomorphic Encryption Over the Integers

Is that a single attacker with a simple desktop computer, or is that someone with a bot net or super computer?
I'd say it depends of value of the assets. If you need to protect data worth let's say $10m, you can assume someone could throw at least money up to that value to get it. Converting money into computational power with AWS or Azure is pretty trivial today, and it can be done by virtually anyone.

And of course state-level parties might be interested in your data for whatever reason they like (for example NSA, interested even in your private photos - see Can They See My Dick?), and they might throw computational power of much higher value that traditional cyber-criminal could justify in given case.

So in short: always assume adversary might have supercomputer or powerful botnet.