[FEATURE]: Retry: allow user to change "exponential backoff" to "fixed interval"

[tgrushka]

Feature hasn't been suggested before.

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Describe the enhancement you want to request

Exponential backoff was added in #1712 , but the interval grows too long very quickly.

After only 13 retries, the delay is 4 hours.

If you leave a task overnight to finish when the API becomes available, the next day it will still be stuck in retry mode with several hours to go when the API has been available for hours.

Retrying manually by interrupting and redoing often results in success after only a short waiting period.

The retry interval and strategy should be user-configurable. Exponential is overkill, and seems to have no limit.

If this is an experimental feature, it should be able to be turned off.