Mastodon now has a quoting feature, you can find out how to use it in the guide at:
➡️ fedi.tips/why-cant-i-quote-oth…
The guide also answers lots of questions about quoting in Mastodon.
How do I quote posts in Mastodon? | Fedi.Tips – An Unofficial Guide to Mastodon and the Fediverse
An unofficial guide to using Mastodon and the Fediversefedi.tips