Strategies refer to high-level actions to be developed to achieve defined objectives, while solutions are related to how these actions will be implemented.
For example, to ensure the objective of recovering operations in a defined timeframe, the strategy adopted may be the use of an alternative site, and the solution would be the definition of the alternative site (e.g., by hiring a third party to provide the alternate site, or the organization can build its own main site.
Another example is a backup strategy (which could be incremental, differential, etc.), and the solution would refer to the specific hardware and software bought.
This article will provide you a further explanation 22301:2019: