First of all, to the best of my understanding an audit is no longer required if your (business) profits are less than 8/6% of your turnover and turnover less than 1 crore. If you read the latest text of sections 44AD and 44AB, the clause that mandated as such has been removed. You can read them on the income tax website and come to a conclusion yourself. I searched around and I’m not the only one who thinks so - there are many articles on this like this one from taxguru.
Next, since you have STCG losses you have two routes - file your STCG losses as business losses, or show them separately as STCG losses (in schedule CG). If you have filed returns in the past you have to stick to the choice you made then - there’s no turning back. If however this is the first time you are filing STCG losses, you can characterise them as business losses which may allow you to file the much simpler ITR-4.
The shorter form is tempting, but I would suggest you to consider filing them separately in the ITR-3. The reason is that STCG gains are taxed at 15% but if you show them as business income, they would get charged at your income tax slab. And that would mean 30% (even if you are not at the 30% slab right now, you would surely be there in the future when your income rises). Remember, you cannot change this once you make a choice.
And you can still take advantage of the presumptive tax provisions (44AD and 44ADA - the 6% and 50% ones) in ITR-3 as well. ITR-3 is the general purpose tax form. Anyone who files an ITR-4 can also file an ITR-3 with the same effect.
Like you, I have mixed income from business as well as profession. Ideally, I should be able to claim 44ADA for my professional income and 44AD for business income. However, there are mixed opinions on weather you can do this. Honestly the rules are written in a language that assumes that a person will only conduct a business or a profession, but what if like us he is engaged in both? The rules are a bit muddy when it comes to that.
To be on the safe side I am not taking advantage of these provisions, and filing ITR-3 manually stating actual income and maintaining book of accounts. The safest option according to practicing CAs is to go for an audit on top of this if you can afford it, even if it is not mandated by the law for you. I am most likely not going for an audit this year.
One warning though - if you do take advantage of presumptive income (section 44AD/ADA) then you are required to stick to that for 5 years. If you switch back to showing regular profits and losses before 5 years, you would be subject to a compulsory audit.
This is as far as I understand, and you could/should consult a CA for more clarity.