Here's a simple approach:
Link the Tables: Create a linked record field in Table 2 that connects to Table 1. This allows you to reference and combine data between the tables.
Use Automation: Set up an automation that triggers when a record in Table 2 is approved. The automation would copy or move the data from Table 2 to Table 1, effectively updating Table 1 with the new data.
Concatenation: To "join" or concatenate records, use a formula field in Table 1 that combines values from the linked records. You can also use rollups to aggregate data from Table 2 into Table 1.
Scripted Solution: If more complex concatenation is required, use Airtable's scripting block to write a script that merges the data from Table 2 into Table 1.
This setup allows you to keep your current data in Table 1 untouched until changes in Table 2 are reviewed and approved.