Yes, the helps say that in hebrews 8:6 there is a verb. And the translations are rendering it present tense
First of all, I have to wonder why you feel the need to depend on "helps", if you are truly fluent in Greek.
Secondly, I love how you say (1) "the helps say there is a verb", but (2) the translations are rendering it present tense", as if the translators could be wrong.
Actually, the "helps" say that the verb IS in the present tense:
Εβραίους (Hebrews) 8 - νυνὶ δὲ διαφορωτέρας τέτυχεν λειτουργίας ὅσῳ καὶ κρείττονός ἐστιν διαθήκης μεσίτης ἥτις ἐπὶ κρείττοσιν ἐπαγγελίαις νενομοθέτηται
έστιν ....... V-PAI-3S, of "ειμι".
And that parsing indicates:
"present active indicative"
"3rd person singular"
of the lexical form, "ειμι".
So the verb is EXPLICITLY and UNDENIABLY in the "present" tense.
And that means Jesus IS (currently) the mediator.