According to the third paragraph of Article 59 of the Trademark Law, before the trademark registrant applies for trademark registration, if another person has used a trademark that is the same as or similar to its registered trademark and has certain influence, the exclusive right holder of a registered trademark has no right to prohibit the user from continuing to use the trademark within the original scope of use, but may require him to attach an appropriate distinguishing mark.
Based on the above, if you still use the previous trademark within the original scope (without expanding the production scale), the other party cannot say that you are infringing, but may ask you to add some distinctive marks.
If you don't feel at ease, the other party's newly registered trademark is still in the objection period and has not obtained the exclusive right to use the trademark, you can raise an objection to the Trademark Office before using it, so that the other party's trademark will not be registered and subsequent disputes will be exempted.