Hi there, @romanr.

I agree that it’s very helpful to have this feature available in QuickBooks Online as well. At this time, there isn’t a specific time frame as to when this feature is available.

But let me share this information on how estimates work in QBO. 

An estimate is a quote you provide a customer for products and services. Once an estimate is saved in QuickBooks, that estimate can be turned into an invoice if the customer decides to accept your quote. 

Using an inventory item on an Estimate doesn't affect your inventory count since these are non-posting transactions. Your inventory count is affected once the Estimate is converted into an Invoice or Sales Receipt.

Please know that your voice is more important to us. We take our customer's feedback as an opportunity so we could know about which area of the product we need to improve. Rest assured, our Product Developers are working for this feature to be included in the future.

You can visit our blog site, as mentioned by my colleague @Rasa-LilaM to stay updated.

Also, in case you need more information about managing your QuickBooks account, you can check this link: Help articles.

I’m always around if you have any other concerns.