The iOS 14.5 update has no impact on the conversion integration regarding Google Ads search campaigns.
The only impact will be on display and video ads which are placed within mobile apps (such as the YouTube app). When iOS users opt out from tracking, WBRAIDs will be used instead of GCLIDs. Within the direct Google Ads integration we will still integrate data via the WBRAID parameter, but the attribution process within Google Ads can take around 2 days.