There are several companies that provide this type of service on the market, you can take a look at the reviews online or ask your friends for help.
As far as I know, among all of them, LitExtension is receiving the best reviews on Trustpilot. They provide you an automated migration tool that you can use to migrate all your data such as customers, orders, products, etc. between 2 platforms automatically, accurately and safely at a reasonable cost.
The migration process is fully automated. Thus, you don’t have to keep your browser on or your internet connection alive while the migration process happens. Moreover, there will be no downtime to your source store (your source store still runs normally during the process) and all the newly incurred entities will also be taken care of as they have unlimited recent data migration and smart update service.
With LitExtension, you will only go through 4 simple steps of upgrading from M1 to M2:
Step 1: Register an account or login to LitExtension site
Step 2: Enter your source and target store information
Step 3: Select entities you want to migrate
Step 4: Run demo/ Skip demo and run full migration
Very simple, easy and effective. For more details, you can visit this article on how to migrate from M1 to M2 using LitExtension tool.