sql = f"""INSERT INTO user_apis
  (api_id, user_id, monthly_requests, total_requests)
  VALUES (1, {current_user.id}, 0, 0)"""

1.x

result = db.engine.execute(sql)

2.x

from sqlalchemy import text
with db.engine.begin() as conn:
    result = conn.execute(text(sql)) 
    conn.commit()              #2.x execute now only works with SELECT.
                               #Inserts, Updates and Deletes now must be 
                               #in a transaction and explicitly committed
                               #use engine echo=True to show transaction status

SELECT sql

with db.engine.connect() as conn:
    result = conn.execute(text(sql)).fetchall()

Add this method to do the right thing on both versions.

Then change all your db.engine.execute(sql) to myengine_execute(sql)

def myengine_execute(sql): 
  #If sqlalchemy version starts with 1.4 then do it the old way
  sqlalchemy_version = version("sqlalchemy")
  if sqlalchemy_version.startswith('1.4.'):
    with engine.connect() as conn: 
        return conn.execute(text(sql)) 
  else:
    #otherwise do it the new way with transactions:
    with engine.connect() as conn: 
        result = conn.execute(text(sql)) 
        #print(result.inserted_primary_key()) 
        conn.commit()

upd_sql = "update bankaccount set amount = amount+5e10 where id = 1234567" 
result = myengine_execute(upd_sql)