I have converted to QBO but I have 20+ years in my QBDT file.  Not all of my data converted - ie 2 custom columns on my invoices in QBDT did not convert to QBO - so my QBO file is incomplete.  I would like to retain read only access to my QBDT file and have read conflicting information as to whether that remains for one year after cancelling QBDT subscription or not.   My subscription expires next week and we are not done with our tax return for 2022 yet so I need to be able to access and change data until then.  After that read only access with reporting abilities would be great. I would pay a smaller subscription price for that but don't think $500+/year is an acceptable option.   

Customer support said to open the QBDT file with excel but when I tried that it said the file was too large.  Another said to compress the data and then open to excel but data would be lost so that is not an option either.  Exporting data to excel through reports is cumbersome and time consuming.  I do not want to pay for both QBO and QBDT but feel they are holding my historical data hostage by not allowing access to complete history.   Are there other viable options that small companies are using to access data in old QBDT files?