GXUS
Goldman Sachs MarketBeta Total International Equity ETF
stock NYSE ETF

Since historical returns do not predict the future, the first step towards making this decision would be to recognize that how these funds are different.
VEA & SCHF are very similar, broad, developed market indexes. They are slightly different (82% overlap), but their returns are nearly identical. SCHF holds more large-cap foreign stocks, VEA has more exposure to mid- & small-cap stocks (and holds positions in more than twice as many stocks as SCHF). Geographic distribution is also roughly the same (40% W. Europe, 20% Japan, 12% UK, 10% Canada...).
IDMO uses momentum factors to choose around 200 stocks and rebalances its holdings periodically. The stocks it chooses are almost all held by VEA, so IDMO is really overweighting a somewhat-concentrated subset of stocks, and those stocks - right now- are more likely to be Canadian or German, and much less likely to be in Japan.
Taxable probably makes sense to go VEA or SCHF with their super-low turnover (<5%) and relatively less risk
In your Roth IRA, you can take the risk of IDMO, or pair IDMO with either of the broad market indexes, or an even broader international fund with emerging market equities included like VXUS, GXUS or AVNM so IDMO becomes an overweight of the int'l market more than your sole int'l diversifier.

Since historical returns do not predict the future, the first step towards making this decision would be to recognize that how these funds are different.
VEA & SCHF are very similar, broad, developed market indexes. They are slightly different (82% overlap), but their returns are nearly identical. SCHF holds more large-cap foreign stocks, VEA has more exposure to mid- & small-cap stocks (and holds positions in more than twice as many stocks as SCHF). Geographic distribution is also roughly the same (40% W. Europe, 20% Japan, 12% UK, 10% Canada...).
IDMO uses momentum factors to choose around 200 stocks and rebalances its holdings periodically. The stocks it chooses are almost all held by VEA, so IDMO is really overweighting a somewhat-concentrated subset of stocks, and those stocks - right now- are more likely to be Canadian or German, and much less likely to be in Japan.
Taxable probably makes sense to go VEA or SCHF with their super-low turnover (<5%) and relatively less risk
In your Roth IRA, you can take the risk of IDMO, or pair IDMO with either of the broad market indexes, or an even broader international fund with emerging market equities included like VXUS, GXUS or AVNM so IDMO becomes an overweight of the int'l market more than your sole int'l diversifier.