Should I relocate to Brazil in 2020?

IMO the exposure to overseas has benefits. We had an office in Rio, but I normally only came twice a year. Only benefit was I got to travel around Brazil, but never learn the language. Entry level here is totally different than where you are.
Now will you be paid in Euros and send money here or paid in reals?
I will defer as to investing in an currency exchange money fund ETF in BR. Not a big fan in the markets here.
As to real estate investing, yes you can get a low entry point, but how long it will take in BR to get a good return, is very risky.
As to 2020 in SP (hot area and escalating) We are now #3 in the world as to reported cases. If or when a vaccine is found, BR may not have the resources to get it to all here for a long period of time.

I'm with Tex:  international experience is a great idea, particularly at this stage in your career, and if you're moving with your current employer and a euro-based compensation package.  But take it in two year chunks, at least to start with.  Don't plan on extending your visa until you know that Brazil is for you long-term.

You do not want to come until Brazil re-opens, São Paulo reports that covid-19 is under control, and enough time passes to assure you that they're telling the truth.  2021 is probably a reasonable goal.  Even if you've had and recovered from covid-19, don't push it.  We still don't know the duration or effectiveness of any resulting immunity.

As for investments, I wouldn't move any of your European assets to Brazil for investment purposes yet.  There's no indication that the Real has hit bottom, and assets that are appreciating in Real terms but still depreciating in Euro terms don't sound very interesting to you.   You might want to start testing the waters with Reais from your income once you're settled  - money you won't mind losing - and take it from there.

I forgot to ask, how is your Portuguese?
Take it from one that has to rely on spouse, it is not fun not knowing the language and it is hard teaching an old dog new tricks.
Also will the benefits include a Private health care provider?
As Ab3 said you may want to consider 2021.
Never invest money you may need. Always have 6-10 months in liquid accounts not located in BR.

Hello guys, thanks for your kind feedback!

Regarding my professional mobility: I'm fluent in Portoguese, and my actual company has two subsidiaries in SP and RJ. I shared my wish with the manager, and currently there are no projects involving the HQ and subsidiaries together. Therefore, if I want to expat with the same company, I would be hired locally, following a local HR process, receiving salary in reais and paying rent and taxes with local benefits (the subsidiary offers a complete insurance package). Actually only some managers moved with euro-based compensation packages, but they are executives. So, basically, my willingness to international mobility is not tightly for economic reasons. I would also be interested in following a pós-graduação lato sensu while working, improving my local network. Do you think is still worth it the international mobility without an euro compensation package?

Regarding investments: Actually I'm thinking to move a fair quantity of money in financial products with a great interests rate and low risks, such as "titulos prefixados" (i.e. interest rate a.a. > 4%. In my country you can't have any financial bond with more than 2%) and some stocks in brazilian companies, due to the low costs x stock if converting the euro in reais. The liquidity generated would be reinvested in other financial products in Brazil. By the way, these are just suppositions: actually 1€ = 6,28 reais, with a possible forecast at December 2020 around 6,60. I still have time to see when to invest in the right moment. My emergency reserve remains in Europe.

Could this company hire a Brazilian? In BR workforce, Brazilians come first.
If so it makes it harder for you. The company would have to advise and get approval that no Brazilian can do the job. If approve they would give you a sponsor letter for you to get a work visa.
Being paid in Reals, means BR taxes.

In theory, sounds good, but the risk is BR companies.. Say Petro Bras which was the only bidder on its own energy rights, or Vale. Many have defaulted on their bonds. It will happen a lot in the next few years.
All up to you. Did I mention taxes on CG, dividends, savings, and more.
2% on a Euro is better than 10% on a real. Brazil has been known to "mess" with their currency.

That's a higher risk employment proposition, then.  Two things that could mitigate it for you would be if your starting salary in Brazil is comparable to the euro value of your current salary (that will give you a reasonably good standard of living,  but you will lose ground over time), and if your employer will provide you with a path back to Europe at the end of your visa.
Interest rates in Brazil do look attractive from Europe,  but the real has lost over 38% of its value against the euro so far this year.  That's exactly what I meant above about winning in reais but losing in euros:  your 4% return will look ok in Rio or SP, but will likely be overwhelmed by currency losses.  Much better to keep your capital safe and intact, and invest your European returns in Brazil at first.