Confusion Buying Video Lens for Sony a7iii

[fundoootv]

Hi Good day.
Sorry for a long post... I am messed up with too much info online, so seeking help from forum members...

I have bought Sony a7iii body, but totally confused with a video lens to choose (at present due to budget has to go for only 1 lens - any lens <$1000, better if less best)

Purpose of Usage is making Self Content (not for client): 

• 50% Videos Shoot (Youtube Videos & Short Indie Films but good cinematic quality) 
• 30% Vlogging Videos (Still with tripod in a room not travel handheld, buying external monitor to lookup)
• 20% Still Photoshoot (For Thumbnails & Social Media Graphics)

#1 Most pref. i might need autofocus lens so non professional helper can use it to make my videos, if lets say i am anchoring/acting in video.
#2 Might use with DJI gimble in future, so not too long / heavy lens
#3 Confused with 50 mm vs 35 mm (as most videos will be indoor/rooms, so i think 35 better ?) any disadvantage of 35 over 50 ??? for full frame body
#4 With sony a7iii eye / face tracing autofocus, do we still opt for fixed cinelenses / prime still lenses ? Is focus breathing and light change a big issue in making videos ?
#5 What to choose Samyang cine 1.5  vs Sigma Art vs Sony G vs Other options ? Keeping in mind <$1000 range

A detailed suggestion will be wonderful and life saving...

God Bless...
Sushant

PS: Have recently used a7s2 with Samyang Cine lens 1.5 - the output with proper led lights was decent / good, not out of the world... and sometime face out of focus
       (its a manual lens, too much time consuming retakes, espc if its time to time movement based / kids game / walking type)
       you know many time actors face/body move forward and backward while talking.... bokeh was okaish, as in rooms you really dont have much distance behind...

[mirrorlessNY(youtuber)]

do some research on the new Sony 35mm 1.8,,, good range for indoor, 1.8 bokeh & native AF privileges 

[Fauzan]

I agree the 35 1.8 is pretty much the best bang of the buck right now.

It's not too wide and not too tight, great image quality and AF tracking is pretty neat with the A7 III