Makes sense do a renovation from a homeline?

Hi I have typical case that seems easy but several realtors have contradictory opinions.

House: Old Bungalow, 1.5 bathroom, 3 bedrooms, current price is $570K
Condition:
Kitchen from the 80's, white appliances, medium
Main Bathroom: from the 80's, medium
Basement full finished, high-end from the 70's

Same houses full renovated sells for $640K to $700k max

The question that realtors contradicts is:
Mortage remaining: $285K
Equity: (570K-285K=$285K)

I have $50K from a homeline attached to the mortgage if I invest these $50K distributed:
1) $7k in appliances, $3k in granite, same cabinets
2) $10k in the bathroom
3) $3K in shutters
4) $5K in the second bathroom to covert to full.
5) $20K in the basement to upgrade to 2015
6) Full paint and extras.

The new price + investment is $620K, Gain conservative only $20K ($40K if lucky)
The mortgage would be now $335K
New equity: ($640K-$335K=$305K)
Want to move to a $800K house, also I want to buy first and sell later (banks makes this difficult)

The question that they contradicts: is worth the reno spending $50k from a homeline?
If is spent from the own pocket then is not brainer… But is this case?

I would appreciate your valuable expert opinions.

Thanks a million.

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