I often opening several large spreadsheet files with calc. The each file size are 3MB or more. And often freeze when Calc trying to auto-save all opened files at the same time. The more files opened, the longer it freeze.
Are there options to temporary disable autosave while opening some of large files?
Open Options dialog box, open Load/Save, then choose General, adjust “Save AutoRecovery information” to whatever you want. Maybe you have “Automatically save the document too” checked? If yes try uncheck this first.