Should be fine, that’s just 1000 letters per file…
To upload, create a BE workflow API endpoint and call that repeatedly from a local script with your data, or use the bulk create API to do the same with your data.
Yeah there’ll be a cost of 0.5 per thing, or more depending on the method used, so estimate 2.5 million WU, you can work out the costs
Please have a good long think about the cost of doing this in Bubble. (Please)
If its public data - consider Algolia or something like it. If it’s private consider any of the numerous DB alternatives especially designed for this kind of thing.