Bonds vs ETFs. Which to go for beginner investor and why?

I think it would be a good mix to have both in your portfolio. Bonds are generally stable and less volatile so if you intend to withdraw in a few years (< 5years), maybe bonds are better.

But if you are intending to invest in long term (>10years), going for ETFs is a better choice. It will definitely outperform in the long run.

Probably You mean bond ETFs versus stock ETFs.

Bonds (and bond ETFs) formerly took a relatively high proportion of investor portfolios

because of stability. Currently, in times of very low or negative interest rates, which will stay with us for quite some time, the value of bonds to the retail investor is doubtful. Some analysts with all this debt see an upcoming corporate bond bubble/crisis.

If Your investing horizon is long (more than 15-20 years) You do not need

bonds and could be 100 % invested into very, very broadly diversified stocks (through f.ex. MSCI World ETF)​​​