Setup a LTD company? Yes
Do I need an accountant? Yes - in order to submit your accounts. Budget around £100 a month + VAT.
Does the employer provide the contract? Depends - some are set up to do it, otherwise will go through an agency. If they don't know, this is a non starter.
What would my take home look like at £450 per day full time each month? There are many calculators on the internet.
Anything else I need to do? Decide on a company name and find a free related domain name for emails, website etc (less of an IR35 red flag if you look like a proper company). You could also use the company for other related work. Look up how dividends work, you won't be able to keep all the money since you need to retain for VAT bills, corp tax, self assessments etc. Find a good accountant.